package com.itheima;

public class ShenTu {
    public static void main(String[] args) {
        int a = rabbit(20);
        System.out.println(a);
    }

    public static int rabbit(int c) {
        if (c == 1 || c == 2) {
            return 1;
        }
        return rabbit(c - 1) + rabbit(c - 2);
    }
}
